Mining Containment Systems

Mining operations primarily use HDPE and LLDPE geomembrane liner systems for heap leach pads, tailings impoundments, evaporation ponds, and process water containment. HDPE provides superior chemical resistance for aggressive leachate environments, while LLDPE offers flexibility for settling and uneven subgrades. EFI designs complete liner systems including primary and secondary containment, leak detection layers, and drainage systems tailored to your specific mining application and regulatory requirements.

A heap leach pad is a lined containment area where mined ore is stacked and irrigated with a chemical leaching solution (typically cyanide for gold or sulfuric acid for copper) to extract target metals. The liner system beneath the ore heap captures the pregnant leach solution (PLS) and directs it to processing facilities for metal recovery. Heap leach pad liners must withstand extreme mechanical loading from ore placement, chemical exposure from leaching solutions, and long-term service in harsh outdoor environments.

The choice between double-lined and single-lined containment systems is driven by regulatory requirements and risk assessment. Double-lined systems include a primary liner, a leak detection layer, and a secondary liner, providing redundant containment and the ability to monitor for leaks. They are typically required for hazardous materials, heap leach pads, and tailings with toxic constituents. Single-lined systems are acceptable for benign materials and lower-risk applications where regulations permit. EFI designs both configurations to meet your specific regulatory framework.

Mining liner installations undergo rigorous quality assurance testing including spark testing to detect pinholes in the liner surface, vacuum testing on extrusion welds, and pressurized dual-seam testing on all fusion welds. EFI also performs destructive peel and shear testing every 150 linear feet of weld seam, exceeding industry standards. All test results are documented in a comprehensive QA package formatted for regulatory submission.

Mining applications typically require 60 to 80 mil HDPE liner for heap leach pads, with textured surfaces for slope stability on steeper grades. Tailings impoundments commonly use 60-80 mil HDPE with secondary containment. Evaporation ponds and process water containment may use 40-60 mil depending on chemical exposure and regulatory requirements. EFI's engineering team specifies the appropriate liner thickness based on your site-specific geotechnical conditions, chemical environment, and regulatory framework.